Tentukan f(x) jika : g(×) =3x+1 dan (fog) (x) =2×2-3×+1

fog(x)=2x^2-3x+1
f(g(x))=2x^2-3x+1

Ingat! (fog) = gx dimasukan ke fx, kalau (gof) = fx dimasukan ke gx.

Jawab:
(fog) (x) = 2x2-3x+1
= 2(3x+1)2 - 3(3x+1) + 1
= 2(9x2+6x+1) - 9x-3 + 1
= 18x2 + 6x + 1 - 9x - 3 + 1
= 18x2 - 3x - 1